Allocation of assistance costs: extraordinary costs borne by requesting party after consultation; ordinary costs borne by requested party. Article 10 provides that ordinary costs of assistance are borne by the requested Party unless otherwise agreed, while extraordinary costs, including costs for external advisors connected with litigation or compliance, are borne by the requesting Party where they exceed the specified threshold. The competent authorities must consult in advance when extraordinary costs are likely to exceed the threshold and must consult from time to time about the Article's application.